<!DOCTYPE html>
<html lang="en">
<head>
	<meta charset="UTF-8">
	<title>Document</title>
	<script src="http://apps.bdimg.com/libs/jquery/1.9.1/jquery.min.js"></script>
</head>
<body>
	
<div id="head">
	<img src="/placeholder.jpg" alt="" class="logo">
	<h2>头部</h2>
</div>


<p>
	<input type="button" value="按钮" disabled="disabled">
</p>

<script>
	// sizzle 

	var result = $("#head > img");

	result.on("click",function(){
		$(this).fadeOut().fadeIn();
	});

	setTimeout(function(){
		$("[disabled]").val("延时完成").prop("disabled",false);

	},2000);
</script>
</body>
</html>